fix(ci): upgrade Rust from 1.82 to 1.83 for edition2024 support

Fix for Cargo.toml parse error:
'feature `edition2024` is required'

**Problem:**
The toml crate v1.1.2 requires Rust edition2024 feature, which is not
stabilized in Rust 1.82. This causes cargo to fail with:
'feature `edition2024` is required... requires the nightly release'

**Solution:**
Upgraded all workflow jobs from rust:1.82-bookworm to rust:1.83-bookworm.
Rust 1.83 includes the stabilized edition2024 support.

**Changed:**
- rust-fmt-check: rust:1.82 → rust:1.83
- rust-clippy: rust:1.82 → rust:1.83
- rust-tests: rust:1.82 → rust:1.83

**Note:**
Local development uses whatever rustc is installed (currently 1.83+).
CI now matches this requirement.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.gitea/workflows/test.yml

@@ -10,7 +10,7 @@ jobs:
   rust-fmt-check:
     runs-on: ubuntu-latest
     container:
-      image: rust:1.82-bookworm
+      image: rust:1.83-bookworm
     steps:
       - name: Checkout
         run: |
@@ -47,7 +47,7 @@ jobs:
   rust-clippy:
     runs-on: ubuntu-latest
     container:
-      image: rust:1.82-bookworm
+      image: rust:1.83-bookworm
     steps:
       - name: Checkout
         run: |
@@ -74,7 +74,7 @@ jobs:
   rust-tests:
     runs-on: ubuntu-latest
     container:
-      image: rust:1.82-bookworm
+      image: rust:1.83-bookworm
     steps:
       - name: Checkout
         run: |